# CVE-2026-116725: gbsplay through 0.0.103 Out-of-Bounds Read via mapper_map ROM Bank Index

Status: published. Published: 2026-10-26. Updated: 2026-11-02.

gbsplay through 0.0.103 contains an out-of-bounds read vulnerability in mapper_map() in mapper.c that fails to reject ROM bank indexes beyond the ROM size, causing an underflowed bank length. Attackers can supply crafted .gbr, .gbs or .gb files with malicious bank indexes to make bank_get() read far past the heap ROM buffer and crash the player.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/mmitch/gbsplay/commit/a281d80bc56ed63347daf740a2f7aa4f8516165a

## Affected products and versions

- mmitch / gbsplay (mmitch/gbsplay): ≥ 0; ≤ 0.0.103 (affected, custom). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 6.8 (medium); CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: 0.14% as of 2026-11-02; percentile 3.01%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-125

## Exploit evidence

- exploit: https://hackmd.io/@haindpwn/cve-2026-116725-116726-116727-gbsplay-rom-bank-index-oob-read#Attack-flow (ADP: CISA-ADP)

## References

- https://github.com/mmitch/gbsplay/issues/201 (CNA: VulnCheck; issue-tracking)

- https://github.com/mmitch/gbsplay (CNA: VulnCheck; product)

- https://github.com/mmitch/gbsplay/commit/a281d80bc56ed63347daf740a2f7aa4f8516165a (CNA: VulnCheck; patch)

- https://github.com/mmitch/gbsplay/blob/0.0.103/mapper.c#L71-L103 (CNA: VulnCheck; technical-description)

- https://hackmd.io/@haindpwn/gbsplay-rom-bank-index-oob-read (CNA: VulnCheck; third-party-advisory)

- https://www.vulncheck.com/advisories/gbsplay-through-0.0.103-out-of-bounds-read-via-mapper-map-rom-bank-index (CNA: VulnCheck; third-party-advisory)

- https://hackmd.io/@haindpwn/cve-2026-116725-116726-116727-gbsplay-rom-bank-index-oob-read#Attack-flow (ADP: CISA-ADP; exploit)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-116725; retrieved 2026-11-02; source updated 2026-11-02

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-116725; retrieved 2026-11-02; source updated Not reported

Revision: c1f0e4471b16aa20ef93af02b20d10672f184c3463b325a126b0ce16f932ba29

Canonical: https://y2.dev/cve/CVE-2026-116725

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